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| author | Andy Lutomirski <luto@kernel.org> | 2015-07-15 10:29:34 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-10-01 11:36:25 +0200 |
| commit | 264477bc18b1b34a38b5211a75f2af3a0346f814 (patch) | |
| tree | 264833508c0e508f5fde1201a9bc2e2e46024fe0 | |
| parent | a4896b65ac7a912ff9d4cd9d6956eee83a577bf1 (diff) | |
| download | lwn-264477bc18b1b34a38b5211a75f2af3a0346f814.tar.gz lwn-264477bc18b1b34a38b5211a75f2af3a0346f814.zip | |
x86/nmi/64: Remove asm code that saves CR2
commit 0e181bb58143cb4a2e8f01c281b0816cd0e4798e upstream.
Now that do_nmi saves CR2, we don't need to save it in asm.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/kernel/entry_64.S | 18 |
1 files changed, 0 insertions, 18 deletions
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 06469ee0f26e..28b08345ed07 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1885,28 +1885,10 @@ end_repeat_nmi: call save_paranoid DEFAULT_FRAME 0 - /* - * Save off the CR2 register. If we take a page fault in the NMI then - * it could corrupt the CR2 value. If the NMI preempts a page fault - * handler before it was able to read the CR2 register, and then the - * NMI itself takes a page fault, the page fault that was preempted - * will read the information from the NMI page fault and not the - * origin fault. Save it off and restore it if it changes. - * Use the r12 callee-saved register. - */ - movq %cr2, %r12 - /* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */ movq %rsp,%rdi movq $-1,%rsi call do_nmi - - /* Did the NMI take a page fault? Restore cr2 if it did */ - movq %cr2, %rcx - cmpq %rcx, %r12 - je 1f - movq %r12, %cr2 -1: testl %ebx,%ebx /* swapgs needed? */ jnz nmi_restore |